Go Down

Topic: Proximity Sensor with NAMUR output (Read 2814 times) previous topic - next topic

proteus

Hallo,
I'm a newbie in the ┬ÁC area but I have some knowledge in programing C++, Java, VB.NET. Last week I bought me an Arduino board with an ATmega168. I'm very surprised of easy programing of the board. But now I have a little problem.

I have to read seven different sensors with the baord. Two of the sensors are proximity sensors(proximity switch) with a NAMUR output(NAMUR: constant voltage and variable current). If a metal part is near (<2mm) the switch, I have an output current of <=1mA. If the metal has a bigger distance than 2mm, I have an output current of >3mA. The voltage is the whole time constant at 8,5V.
My idea now is to convert the current signal to a voltage signal with a transimpedance amplifier(http://en.wikipedia.org/wiki/Current-to-voltage_converter).
So I would like to know if somebody has an better and easyier idea how can I measure this signal with my Arduino.
I have attached the datasheet of the sensor below.
I hope my idea is not the only way to measure such a signal.

MarkT

Or perhaps a small value resistor in series with the current and an analog input?
[ I won't respond to messages, use the forum please ]

proteus

At the beginning I was trying to measure with a shunt resistor, but like it seems it was a little bit to big. Now I've tryed a smaller one and it works fine.
@MarkT: Thank you for your post, it make me to try it again. Saved me a lot of time :)

Hello guys,

Even if this thread is almost 3 years old, maybe you are still there :)

Though I have good knowledge about programming, I'm a newbie in electronics. And , like Proteus, I would like to interface a Namur type sensor with an Arduino Uno.
I followed your posts, I understood that this sensor type switches the current flow (<1mA or >3mA) depending if there is a metal part near it or not.
What I did not understand was the answer/idea given by MarkT. He said to use a series resistor. Ok, but from which point to take the signal for the Arduino input ? And how much ohms the resistor should have ?  He said also to use the analog input. Is this safe considering that the maximum accepted voltage is 5V on Arduinos ?

Thank You in advance.

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy